Acetic Acid → tert-Butyl 4-cyclopropylpiperazine-1-carboxylate

Participants

Reaction Conditions

Reaction Steps

MeOH (0.3 mL), ((1-ethoxycyclopropyl)oxy)trimethylsilane (2 g, 11.47 mmol) and acetic acid (1.051 mL, 18.35 mmol) were added to a stirred solution of tert-butyl piperazine-1-carboxylate (1.068 g, 5.735 mmol) in THF (40 mL) under nitrogen. Sodium cyanoborohydride (0.541 g, 8.60 mmol) was added portionwise over a period of 10 mins. The resulting mixture was stirred at 60° C. for 24 h. The reaction mixture was evaporated to dryness and mixed with water (80 mL) and 1M HCl (25 mL). This solution was washed with EtOAc (2×50 mL), the aqueous layer was basified with K2CO3, and extracted with EtOAc (2×30 mL). The organic layers were combined, washed with saturated brine (30 mL), dried over MgSO4, filtered and evaporated to afford tert-butyl 4-cyclopropylpiperazine-1-carboxylate (0.792 g, 61.1%) as a colourless oil which crystallised on standing.

Provenance & Evidence